Functional factors are also important in the meaning of
architecture. Unlike the other fine arts, architecture is built for practical
use (commoditas or utility). Each building type (town hall, castle, cathedral,
prison, office building) has its own functional requirements and these
are intimately linked with the meaning of the architecture. Of course,
some buildings are constructed simply to fill a need, while others are
intended to be monuments to the concept that the building type embodies.
The uses of buildings change over time, and it is often instructive to
compare current and past uses of a structure. In general, the history of
architecture has been one of increasing diversification, with more and
more specialized buildings for specific functions.

Functional and structural factors have not always been
of primary importance, however. Nineteenth century architects were concerned
to articulate the purpose of their buildings in a visible manner through
the choice of style. Historical or ideological associations were often
the basis of these choices. Kings borrowed architectural forms from either
the Roman Empire or Louis XIV to align themselves with the past ages of
glory. Architectural forms, like clothing, announced the role of the building
in society just as different costumes were associated with different occupations.
In the twentieth century, a more utilitarian functionalism came to the
fore, emphasizing structural principles over the social uses of the building.
Modern architects have considered it a matter of principle not to disguise
the bearing elements in a structure, but to reveal and even celebrate them.